ポリケイ皮酸ビニルの光学増感に関する一考察

抄録

Poly (vinyl cinnamate) is optically sensitized by aromatic nitro compounds and aromatic carbonyl compounds. The common characteristic of these compounds is that fluorescence is scarecely to be observed: the “ forbidden” conversion to the triplet state (T-state) is essentially complete (ref. 6). This fact may suggest that the T-state of the sensitizer plays an essential role on the optical sensitization of poly (vinyl cinnamate). Another experimental fact giving support to the T-state hypothesis is that 4-bromo-1, 8-phthaloyl naphthalene shows the more sensitizing property than 4-chloro-1, 8-phthaloyl naphthalene. The sensitized photo-dimerization of cinnamoyl groups of poly (vinyl cinnamate) may involve energy transfer from the lowest T-state of sensitizers. Therefore, the compounds, of which the lowest T-state energy is larger than that of cinnamoyl group, will have the property of sensitizing poly (vinyl cinnamate). The measurements of the sensitizing effects on poly (vinyl cinnamate) of mixtures of two kinds of aromatic nitro compounds and ketones shows that the relative sensitivity of mixed sensitizers is equal to the sum of those of each compound at the low concentrations of them, and agrees with that of the compound having the smaller Tstate energy at the high concentrations, respectively. These results are naturally expected from the T-state hypothesis.